Electrical recording instrument for electrocardiographs



March 25, 1952 J. LUKACS 2,590,554

ELECTRICAL RECORDING INSTRUMENT FOR ELECTROCARDIOGRAPHS Filed Dec. 4, 1946 s Sheets-Sheet 1 T: 1- 3 ATTORNEY March 25, 1952 .J. LUKACS ELECTRICAL RECORDING INSTRUMENT FOR ELECTROCARDIOGRAPHS 5 Sheets-Sheet 2 Filed Dec. 4, 1946 INVENTOR. mm fl luau W (:LLLL,

riff/ .7 04 2 March 25, 1952 J. LUKACS ELECTRICAL RECORDING INSTRUMENT FOR EILECTROCARDIOGRAPHS 3 Sheets-Sheet 3 Filed D80. 4, 1946 IN VE/VI'OE ATTOUEY Patented Mar. 25, 1952 ELECTRICAL RECORDING INSTRUMENT FOR ELECTROCARDIOGRAPHS Joseph Lukacs, Astoria, N. Y., asslgnor, by mesne assignments, to Technicon Cardlograph Corporation, New York, N. Y.

Application December 4, 1946, Serial No. 714,084

6 Claims. 1

invention relates to electrical recording instruments for electrocardiographs.

The primary object of the invention is to provide an electrocardiograph with an improved recording instrument for obtaining direct-reading electrocardiograms.

The above object of the invention and objects ancillary thereto will be fully understood from the following description, reference being had to the accompanying illustrative drawings.

1n the drawings:

Fig. 1 is a perspective vlew'of a recording instrument embodying the present invention;

Fig. 2 is a sectional view on line 2-2 of Fig. 1;

Fig. 3 is a perspective view or associated parts 01' the instrument;

Fig. 4 is a detail sectional view on the line 4-4 of Fig. 1;

Fig. 5 is a. bottom perspective view of the instrument;

Fig. 6 is a sectional view on Fig.

Fig. '1 is a sectional view on the line 'l-I of Fi Fig. 8 is a view of the platen on the line 8-8 of Fig. 6;

Fig. 9 is a detail sectional view on the line 99 of Fig. 1;

Fig. 10 is a perspective view of the magnetomotive device;

Fig. 11 is a sectional view on of Fig. 10;

Fig. 12 is a perspective view of the movable coil of the magneto-motive device;

Fig. 13 is a perspective view of the diaphragm on which the coil bobbin is mounted and which is connected to the pen-operating rod.

Referring now to the drawings in detail, the recording instrument embodying the present invention comprises a main frame I having a flat, top panel 2. A pen or scriber 3 is mounted for oscillatory movement over panel 2 in a plane parallel to the plane of said panel for recording the electrocardiogram on a paper web W. As here shown, the scriber 3 has an electrically heated coil-tip 4. and web W is or the thermalresponsive type whereby the heated tip of said pen or scriber acts on said web to produce the trace or electrocardiogram during movement of the web in the direction of its length. It will be understood, however, that an inking pen, supplied with ink, may be used instead of an electrically heated scriber and that in such case the web W need not be of the thermal-responsive typ The present the line 66 of the line li-II The scriber 3 is mounted on and is actuated by an oscillatory spindle 5 pivotally mounted in bearings 6 (Fig. 5) provided in brackets I. Said spindle is provided with a crank arm 8 to which the operating rod 9 is pivotally connected. Said rod 9 is reciprocated or oscillated linearly, in the direction of its length, by a magneto-motive device M which is operable under the control of amplified small voltages in the operation oi the electrocardiograph. Said magneto-motive device will now be more particularly described herein with reference to Figs. 10 to 13.

Said magneto-motive device M for operating the scriber 3 comprises a permanent annular magnet In, the end plates 12 and I4, and the center-pole core It, forming a magnetic circuit. As here shown, the magnet Ill and the plates l2 and H are held together, mechanically and in magnetic-circuit relation, by a plurality oi cir cumierentially spaced brass or other non-magnetic screws iii. The center-pole core i6 is secured in plate I2 preferably by a press fitting in the opening 20 of said plate. Said core I6 is of circular cross section and has an end part 22 which together with the central circular part 24 forms an annular axially-extending air gap in which the coil 26 is movable. The center-pole core l6 has an axially-extending conical portion 28 between the end cylindrical part 22 and the opposite end cylindrical portion 30 which is secured to plate i2, said portion 28 tapering toward said part 22. The air gap-defining part 22 of core l5 has an axial recess 32 which is conical or tapers inwardly, thereby providing the core part 22 with an annular wall which is of decreasing radial thickness in a direction extending axially of the core toward the outer end of plate l4. Also, as shown plate (4 is of varying axial thickness, the thickness of said plate increasing to a maximum in the central or gapdefining part 24 thereof. By virtue of this construction of core Hi and of plate It, magnetic leakage, which would otherwise occur. is reatly reduced, and the magnetic flux is caused to pass across the air gap between parts 22 and 24 along substantially parallel lines radially of the central longitudinal axis of the magnet. Further it will be observed that the plate I2 is provided with a chamfered outer edge 34 which aids in reducing magnetic leakage. Preferably the magnet In is formed of Alnico, and the plates 12 and I4 and the core l6 are preferably formed of hot rolled ingot iron or SAE 1010 annealed steel.

The winding of the movable coil 26 is carried by a bobbin 36 which is strong and of light weight. Said bobbin 36 is preferably formed by molding the same of nylon, but can be formed of "bakelite" or of any other suitable material. As shown, said bobbin is provided with a flange a by which it is secured to the central ring III of the flexible diaphragm 42. The outer ring I of said diaphragm is clamped between a spacer ring 4' and a retaining ring 48. As here shown. a plurality of screws II are utilized for securing diaphragm 42 between rings 46 and 48 and for securing the assembly of said rings and diaphragm and the coil which is carried by said diaphragm to plate ll. Diaphragm 42 is formed of thin flexible sheet metal and has a plurality of webs 52 which extend between the outer clamped ring II and the inner ring 40 to which the bobbin is secured. A cap it is secured to the inner ring ll of diaphragm 42, and rod 9 is connected to said cap at the center point thereof so as to project axially of the winding of the coil 26. It will be understood that coil 26 is connected to the output circuit of an amplifier of small voltages, such as those involved for example in the operation of an electro-cardiograph. The device M is provided with means for flattening the response of the movable unit of the device for correction of the amplitude variations thereof as resonance of said movable unit is approached. For this purpose an endless metal ring El, preferably of copper, is mounted on bobbin It in position centrally of the coil winding in insulated relation thereto. Said ring El provides means for damping vibrations or oscillations of the movable coil unit for providing correction for the natural change in amplitude of oscillations of the movable coil unit as resonance is approached. thus flattening the response and preventing over excursion of the pen or stylus in the operation of the latter for forming the trace on the paper web.

The magneto-motive device M is carried by frame I and, in accordance with the present invention, is supported adjustably in position on said frame so that spindle may be disposed with its axis perpendicular to the correct plane of oscillation of the scriber 3 whereby the tip 4 of said scriber is oscillated in a plane parallel to the flat record-receiving plane of the web W during the longitudinal movement of the latter.

For this purpose the magneto-motive device M is secured in a bracket 56 and the latter is adjusttably secured to panel 2 of the frame I by the screws 58 and the companion bushings I (Figs. 1 and 9). As shown, the bushings ill are adjustably threaded into the panel 2 and the screws 58 pass through the bushings and are threaded into the upper edges of the bracket 58. It will be understood that by adjusting said companion screws and bushings as may be required the magneto-motive device M can be easily adjusted so that spindle 5 is perpendicular to the writing surface of the web W and, concomitantly. so that the tip 4 of the scriber moves in a plane parallel to said writing surface. Spindle I passes through an opening 6! in panel 2, said opening being sumciently large to permit lateral movement of said spindle for adjusting the latter pursuant to the adjustment of the magnetomotive device M as described above.

The panel 2 is provided with an opening 62 in which a platen 64 is disposed as a support for the web W for operation thereon of the scriber 3. Bald platen is carried by an adjustable support or bracket M which is vertically movable. rectilineariy and normal to the plane of the platen, for adjusting the position of said platen so that the web may be properly adjusted to the tip I of the scriber. Said bracket 68 has a depending portion ill which slidably engages a guide 16 carried by the frame i below panel 2 thereof. Said bracket portion 68 has a lateral extension I2 which projects through a slot I4 in guide member ID for movement longitudinally of said slot to permit vertical adjustment of said bracket. A screw-threaded rod 16 is in threaded engagement with extension 12 and is provided with an operating knob 18 located at the top of panel 2 for convenience in adjusting the platen 84. It will be understood that rod 18 is rotatable but is held against longitudinal movement, as. illustrated in Fig. 6, so that rotation of said rod, accomplished by turning knob 18, results in rectilinear movement of bracket 66 and the platen 64 carried thereby. Platen 6| is pivotally mounted on bracket 66 for pivotal movement in opening 62, as indicated by the positions of said platen shown in full and dotted lines, respectively, in Fig. 4, to facilitate the positioning of the web W from the supply roll R on the platen. This pivotal mounting comprises a rod I8 carried by bracket 66 and ears Bil carried by the platen, said ears being pivotally mounted on said rod. The platen is provided with a downwardly-extending plate 82 having a recess ll therein positioned to be engaged by a spring-pressed pin 86, in the normally horizontal or operative position of the platen, for releasably holding the platen in operative position. A finger piece 88 is provided on the platen at one side edge thereof and projects upwardly through opening 82 to facilitate turning of the platen on rod I8 when it is desired to uncover opening 62 for obtaining access to the end of the web of the supply roll R in the operation of positioning the leading portion of said web on the platen. and for returning the platen to its normal web-supporting position.

The means for moving the web in the direction of its length during the operation of the instrument comprises a roller 86 carried by a rotary shaft 92 actuated by an electric motor 94 through suitable speed-reduction gearing with which said motor is equipped. Spring-pressed rollers 86 hold the web w in frictional engagement with roller whereby the latter is eifective to advance the web at a uniform speed. Said rollers 98 are fixed to a rotary shaft 98 which is journalled at its ends in the arms lllfl which are pivotally mounted onacrossrod Hi2. Atension spring I is connected at one end thereof to a cross member I", which extends between arms I00, and at its opposite end to a pm I" which is fastened to the bracket Ill. The forward ends of arms W0 are connected to each other by a strap III which also provides a cutting edge for severing the web at the part thereof forwardly of the drive roller 90. It will be understood that the spring ill normally holds the rollers 96 resiliently against the web for pressing the latter against the driving roller an and permits arms I" and the roller shaft 98 carried thereby to be moved away from the roller 90 to permit the leading edge of the web to be placed between said roller 90 and the companion rollers 06. A pivoted pressure plate H3 is mounted on a shaft H5 in position to engage the roll R of the web to frictionally retard the unwinding of the web from said roll, so as to tension the web sufficiently to prevent slack therein during movement of the web over the platen 04. An adjustable spring II! is connected to shaft II! and bears on plate III to regulate the pressure of said plate on the web roll R. A spindle II! fixed at one end thereof in bracket I It provides a support for the web roll.

Provision is made for recording a calibrating trace or record on the web W for testing the recording instrument and to check the operation thereof. For this purpose the instrument is provided with a pulse wheel Ill carried by shaft 82 at one end thereof for actuation by said shaft. Said pulse wheel I engages a switch-actuatin member lie of a microswitch H8 for intermittently closing an electric circuit to which a standardization voltage, usually one millivolt. is

applied when it is desired to test or calibrate the instrument. It will be understood that a suitable switch (not shown) is provided for opening the circuit of pulse switch ill during the operation of the instrument for recording a cardiogram on web W. v

A step-down transformer I which, as shown in Fig. 1 is mounted on the panel 2, is provided for supplying current at reduced voltage for heating the thin coil-tip I of the pen or scriber 2 which as hereinbefore indicated forms the cardiogram on the web W by thermal action. The pen or scriber 3 comprises the thicker wires I22 which are connected in series with the thin tip 4. Said wires I22 are carried by an insulation plate I2! and are held in spaced relation by the insulation strips I26. An insulation spacer I28 is provided for holding wires I22 in spaced relation near the tip 4. Terminals III) are provided on panel 2, as shown in Fig. 1, for supplying current to the scriber, the wires I22 of said scriber being connected to said terminals and the latter bein connected to the low-voltage side of transformer I20. It will be understood that the pen or scriber 3 may be of any suitable construction other than that herein specifically illustrated or described, and further it will be understood that as hereinbefore indicated an inking scriber or pen may be utilized in lieu of the heated scriber 3.

As illustrated in Fig. 1 a pilot lamp I32 is provided on the panel of the instrument. This pilot lamp is connected to the electric circuit (not shown) of the electrocardiograph, under the control of a suitable switch, to indicate that the electrocardiograph is in operation.

Various changes in the details of construction and in the arrangement of parts may be made without departing from the underlying idea and principles of this invention within the scope of the appended claims.

Certain features shown but not claimed herein are claimed in the divisional application Serial No. 243,724, filed August 23, 1951.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. In an electrical recording instrument of the designated character provided with a platen for a web on which the record is made during the travel of the web over the platen. and means for mounting a recording scriber for oscillatory movement over said web in a path transversely of said direction of web movement; means mounting said platen in position for operation of the scriber thereon, said mounting means comprising a frame and a bracket carrying said platen and mounted for rectilinear movement on said frame in a direction normal to said platen, and movable means connected to said bracket for moving the 6 latter rectilineariy for adjusting the position of said platen in relation to the scriber.

2. In an electrical recording instrument of the designated character provided with a platen for a web on which the record is made during the travel of the web over the platen, and a scriber for making the record on said web; a frame having an opening, means mounting said platen on said frame in said opening in position for operation of the scriber thereon, said mounting means comprising a bracket carrying said platen and mounted for rectilinear movement on said frame in a direction normal to said platen. and movable means connected to said bracket for moving the latter rectilinearly for adjusting the position of said platen in relation to the scriber. said bracket having a screw threaded part and said movable part comprising a screw threaded member in engagement with said threaded part of the bracket and rotatably mounted in said frame and held against rectilinear movement.

3. In an electrical recording instrument of the designated character provided with a platen for a web on which the record is made during the travel of the web over the platen, and a scriber for making the record on said web; a frame having an opening, means mounting said platen on said frame in said opening in position for operation of the scriber thereon, said mounting means comprising a frame and a bracket carrying said platen and mounted for rectilinear movement on said frame in a direction normal to said platen, and movable means connected to said bracket for moving the latter rectilinearly for adjusting the position of said platen in relation to the scriber, means for mounting a web roll in position below said frame, and means for mounting said platen for pivotal movement on said bracket for pivotal movement in said opening from an operating position of the platen, in which said opening is substantially closed by the platen, to a retracted position in which said opening is uncovered to permit the web from said roll to be drawn through said opening and positioned over said platen.

4. In an electric recording instrument of the designated character provided with a support for a web on which the record is made during the travel of the web, and means for mounting a recording scriber for oscillatory movement over said web in a direction transversely of said direction of web movement; means mounting said web-support in position for operation of the scriber thereon, said mounting means comprising a stationary frame and means carrying said web-support mounted in said frame, said websupport being movable in said frame to an inoperative position in a direction transversely of the plane of operation of said scriber and to an operative position in a direction transversely of said plane, and means for moving the web in the direction of its length when said web-support is in said operative position thereof, said frame having a portion disposed in a plane parallel to said first mentioned plane, said portion having an opening defined therein. said web-support being disposed in said opening in both of said positions thereof.

5. In an electrical recording instrument of the designated character provided with a platen for a web on which the record is made during the travel of the web over the platen, and means for mounting a recording scriber for oscillatory movement over said web in a path transversely of said direction of web movement; means mounting said platen in position for operation of the scriber thereon, said mounting means comprising a frame and means carrying said platen and mounted for rectilinear movement on said frame in a direction normal to said platen, and movable means connected to said platen-carrying means for moving the latter rectilinearly for adjusting the position of said platen in relation to the scriber.

6. In an electrical recording instrument of the designated character provided with a. platen for a web on which the record is made during the travel of the web over the platen, and a scriber for making the record on said web; a frame having an opening, means mounting said platen on said frame in said opening in position for operation of the scriber thereon, said mounting means comprising means carrying said platen and mounted for rectilinear movement on said frame in a direction normal to said platen and movable means connected to said platen-carrying means for moving the latter rectilinearly for adjusting the position of said platen in relation to the scriber, means for mounting a web roll in position below said frame, and means for mounting said platen for pivotal movement in REFERENCES CITED The following references are of record the file of this patent:

UNITED STATES PATENTS Number Name Date 1,646,940 Swift Oct. 25, 1927 1,927,899 Mylius at 8.1 Sept. 26, 1933 1,950,832 Winter MM. 13, 1934 2,061,457 Finch NOV. 17, 1936 2,148,188 Chappell et al Rb- 21, 1939 2,170,505 Peters Aug. 22, 1939 2,267,465 Jakosky Dec. 23, 1941 2,331 ,205 Lenehan Oct. 5, 1943 2,369,922 Shamah Feb. 20, 1945 2,391,765 Artzt D80. 25, 1945 2,412,639 Traugott Dec. 17,1946 

